CIS vacuum hose connection. Help!

[Mookster]

I have a 1983 911SC that I am in the process of replacing my CIS vacuum hoses.

The engine is still in the car.

I have removed a 3mm I.D. hose that connects on the control servo (left side of the engine bay) and the other end that connects to the aux. air regulator (right side of engine bay). What I didn't realize that it had a third connection behind the CIS air box. Inadvertently when removing the vacuum line, the third connection came off from an unknown location. Where does the short 3-4 inch connection hook into behind the CIS air box?

If someone has a picture showing the connection fitting it would greatly help. I will have to blindly reconnect the hose.

Thanks for you help in advance.

[Hladun]

http://www.pelicanparts.com/911/911_Parts/911_1978-83_parts.htm

[Mookster]

I have had the chance to review the link. It is missing the vacuum hoses in question.

After reviewing the link/K-Jetronic 911SC (second choice), I still cannot tell where the vacuum hose off part 49, the aux. air reg., connects to the control servo and CIS box. The hoses in question are not within the parts schematic

If you look at page 71, the Parts and Technical Reference Catalog, cruise control diagram, you can see the vacuum hose configuration (the parts are not listed).

If you have an engine with CIS out of your car can you see where the small vacuum hose connects?

Any help is appreciated.

[azasadny]

Mookster,

When I replaced all of the vacuum hoses on my '74, there were a few that I replaced with 1/2" pressure hose, like you use for air tools and air compressor lines. Pretty stiff and unyielding, but a few hoses get close to heat-producing areas and the replacement hoses worked out nice. Just a suggestion...

[Hladun]

Are you talking about hose 53 in the second diagram (http://www.pelicanparts.com/911/911_Parts/1978-83/1-7-3.JPG)? Mine's a 78, but the hose, part 53, has multiple branches. Has someone disconnected the AAV (part 49) on your car and replaced the hose with one that doesn’t have a branch? The hose at part 55 connects to part 28. Part 46 is the AAR, the AAV can be disconnected because it does nothing but cause startup backfires.

[Mookster]

The vacuum lines that I am replacing or not listed in the links.

I have purchased the replacement vacuum lines.

The vacuum hose that I trying to replace (3mm I.D.) has three connection points and runs along the back of the engine bay.
1. The first connection is at the cruise control servo on the left side. I am refering to the narrower of the two vacuum lines.
2. The second connection is at the additional air valve located in the back of the engine bay on the right side. The hose fits on the outer fitting facing away from the engine.
3. The third connection point is unknown. The unknown connection T's off the two connections. The hose is abount 4 inches and connects behind the CIS box somewhere.

Please help me find the third connection fittings connection point.

Thanks in advance for your help.

[cmonref]

A 3 mm vacuum line that connects behind the airbox? I would suggest that this line is #26 on picture 1/7/3, connecting item #15, not #49. When the cruise control is added, that hose is cut and a "T" is inserted to connect the cruise control. A short stub from the "T" goes to the throttle valve to provide vacuum to both devices.

For working on the ports on the throttle valve, working "blind" is all you have -- unfortunately. Hook up both ends of the assembly and see where the 4" stub goes. If it is not close to the throttle valve, reverse the assembly and try again.

You are gonna have to get real good with a mirror and light to see what is behind the airbox and throttle valve. The alternative is to drop the engine, which you probably do not want to do.

Just wait until you have to replace the oil pressure switch. It is a worse nightmare, 'cuz it is even HARDER to reach.

[William Miller]

Two of the 3 that you described are vaccume actuated devices. The third most go to a vacuume source. Most likely the throttle body a Brian Described. The easiest way to get to it will be to remove the heater fann and associated ducts and reach your left arm arround. There are two connections on the "Front" side of the throttle body. One of them is the timing advance (Red) and the other one is probably now empty.
One is above the throttle plate and one is below when the plate is closed.

If you can't get to it that way you can do a "partial engine drop"
Just remove the 2 engine mount bolts on tha back and lower the engine about 3-4 inches. Watch your wires and other conections as you go down and stop if anything get's tight.
Good Luck!

[ohecht]

I found a broken line that led through the hole in the firewall at the top-center-rear(front) of the engine compartment. I had no simptoms, and had wondered about it for years. When I dropped the engine for other reasons, I found the other end under the car, where it connected to a hard metal fitting at the entrance to the center tunnel (where the shift linkage, etc. exits). I think it is either a vacuum source for the brakes, or a vent for the fuel tank that goes to the charcoal? canister in the engine compartment (pass. side). If it is for the brakes, then my brakes should be awesome with power assist restored, since I have always felt they were strong the way they were.

This may not be it, but it is the only ~3" ID line I can think of near that part of the engine. I think all the lines to the TB area are much smaller.

Olivier

[mtelliott]

ohecht:

You are correct, the vacuum going to the tunnel is for the gasoline expansion tank and runs to the charcoal canister.

Mookster:

I have the vacuum connections for an 82 on a file at home that I can send you if it helps. I don't know the difference between 82 and 83 but I know that is seems to differ between years significantly. Send me a PM if you want the 82 version and I will e-mail from home. I went through this very same thing just a month ago.

From memory, I believe that it connects to one of the vacuum ports off the car front side of the throttle body. Not sure if it was the top or bottom one. Of course, 83 may be different.

[ohecht]

There are definitely some ports on the TB that are almost impossible to find if you don't know exactly where they are. I have disconnected lines there and still had to look for the connection again 5 minutes later!

Olivier

[Mookster]

Thanks to all that responded. It's forums like these that save me a ton of money that I would have had to pay my local wrench to bail my butt out.

The mystery 4" vacuum hose connected to the throttle body on a fitting facing the front of the car.

The fitting is very well hidden by other hoses and fuel lines. The vacuum line can be connected (with alot of swearing) without the dismantling of the CIS components or a partial engine drop.